The topic isn’t one the NFL’s MVP considers often. So for a moment, Adrian Peterson nods and gives it deeper thought.

Jerome Felton, Toby Gerhart. Their paths to this point.

Tortuous. Complex. Often frustrating.

Just what is it really like to be Adrian Peterson’s fullback? His back-up?

Peterson, the seventh pick of the 2007 draft, the former Rookie of the Year, the five-time Pro Bowler with the $96 million contract and his eyes set on chasing down a 2,500-yard season can’t help but shake his head.

“I do think about it sometimes,” Peterson says. “No matter how good of a player you are, sometimes you get stuck and you just have to deal with your situation and keep pushing until that opportunity comes.”

CARLOS GONZALEZ &#x2022; cgonzalez@startribune.com

Toby Gerhart (32) still is waiting for his shot to be a starter or even a major contributor, stuck behind Adrian Peterson, while fullback Jerome Felton (42) earned a Pro Bowl berth last year despite never carrying the ball thanks to his blocking for Peterson.

But when will it come, if at all?

After four seasons of frustration with three teams, Jerome Felton almost quit, tiring of bouncing around and having the year-round investments pay so few dividends. In chasing opportunity, he felt like a snorkeler trying to corral a school of minnows with his bare hands. Then he landed in Minnesota in 2012, partnered with Peterson and became an instant Pro Bowler.

Now Felton owns a three-year, $7.5 million contract.

Gerhart? He’s been around Peterson — or more exactly behind the star back — since being drafted in 2010. Upward mobility isn’t exactly a perk on the Vikings’ depth chart. So Gerhart’s path toward excellence remains stonewalled.

He enters the final year of his rookie contract with no promises for his football future.

“I feel like I can be a starting back and a premier back in this league,” he says. “We’ll see if I get that opportunity.”

Beneath the surface of Peterson’s 2012 MVP brilliance was a fascinating reminder about football’s random twists of fate. One star’s talent provided Felton his golden opportunity. For Gerhart, it’s been an electric fence.

“This league can be cruel,” Peterson admits.

Buried under the wait

Felton’s first carry last season didn’t come during the preseason, the regular season or even during a lopsided playoff loss in Green Bay. Twenty-one games passed. Felton played more than 400 snaps — and took zero handoffs.

His first carry as a Viking, it turns out, came Jan. 27. On a handoff from Russell Wilson. In Honolulu. With Elvis Dumervil bringing him down after a 7-yard gain at the Pro Bowl.

Felton had three other rushes that day, including a 3-yard fourth-quarter touchdown, enough to stimulate new proposals for Vikings coordinator Bill Musgrave.

“Maybe I can lobby for a few more touches,” he jokes.

In reality, Felton surrendered that vision long ago. Sure, after a stellar career at Furman that included a school-record 63 TDs, he had initial visions of becoming a punishing ball carrier in the NFL.

The most optimistic believers saw him in the mold of Jerome Bettis. Felton envisioned a Mike Alstott-type role. But NFL personnel folks felt he fit as nothing more than a rugged blocking fullback. And so quickly, dreams gave way to survival instincts.

Sure, Felton would have loved if his path from draft weekend 2008 to his first Pro Bowl had been quick, painless and without detour. It was everything but.

Those hunches Felton had during the fifth round of the ’08 draft that he’d get a call from Arizona or Buffalo? Detroit traded up and phoned instead.

Talk about bad timing. As a rookie, Felton was part of the most discouraging death march in league history. Detroit went 0-16.

Talk about a frustrating fit. Following that collapse, Lions coach Rod Marinelli was fired, his staff gutted. In came new coach Jim Schwartz and offensive coordinator Scott Linehan plus No. 1 pick Matthew Stafford. Just like that, even with Felton sharpening his skills under running backs coach and former Pro Bowl fullback Sam Gash, the need for a road-grating fullback diminished.

Two more seasons passed. The Lions unleashed young receiver Calvin Johnson and went pass-happy.

Felton made it deep into the 2011 preseason before being released.

And then after being claimed on waivers, a promising chance in Carolina derailed when the Panthers’ “Smash and Dash” running attack led by DeAngelo Williams and Jonathan Stewart morphed into “The Cam Newton Show.”

Felton quickly slid again into irrelevance, was released in November and finished 2011 with a safety-net stop in Indianapolis, wondering if his dream was disintegrating.

“You see it happen to guys all the time,” he says. “You’re with a guy one day, he’s gone the next and he never pops back up. Anywhere.”

Imagine the pessimism Felton felt as he hit free agency in 2012. Since sixth grade, he had been convinced he’d make it big. During his first four NFL seasons, he often told friends he was one of the best fullbacks in the league.

But he was all too low on proof and suddenly his motivation to attack his training, to stick to a strict diet, to invest everything he had in simply finding a chance dipped.

“Obviously it’s a dream to play in the NFL. But I felt like I was being cheated out of the dream,” Felton says. “Look, this league doesn’t owe you anything. It never will. But when you dream about it and you work so hard to get here, you feel like I didn’t get the experience I thought I was going to have.”

In the shadow

If anyone can relate, it’s Gerhart, now in his fourth year as a Peterson insurance policy.

By now it’s well-documented that the reigning MVP has announced his quest, as preposterous as it sounds, to rush for 2,500 yards. When Gerhart heard about that goal for the first time, he swallowed hard.

“I was like, ‘Twenty-five-hundred, huh? … That dude’s not coming off the field ever this year.’”

It’s easy to forget that the last time Gerhart had a chance to be an every-down force, he was a headline stealer. Like Peterson, he is a former Heisman Trophy runner-up, completing his senior season at Stanford in 2009 with 343 carries, 1,913 yards and 28 touchdowns.

In his best game, he gashed Oregon for 223 yards and three TDs on 38 rushes.

Last season? He had 50 carries for 169 yards. That in a year that began with everyone thinking he’d be a workhorse early as Peterson worked back from his torn ACL.

“I worked so hard all offseason preparing to be the guy,” Gerhart says. “I think everyone was expecting career highs for me in every category. It turned out to be the exact opposite.”

Lost in the celebration of the superstar’s amazing recovery was the anxiety of the forgotten man. Gerhart’s impatience peaked in Week 3 when he lost two fumbles in a minute and a half when called on to close out a 24-13 upset of San Francisco.

“That was a byproduct of being a frustrated runner,” Gerhart says. “No way around it. In that four-minute situation, we’re taught to get what we can and shoot down to the ground. Don’t try to make a play. For me, I was getting my first carries in a while so I was trying to make something happen. … That was my nightmare game.”

Gerhart always has accepted his role with Vikings coach Leslie Frazier labeling his No. 2 running back “a class guy,” “the ultimate team player,” and “one of those guys you’ll always pull for.”

Still, the raw numbers sometimes annoy Gerhart.

At Indianapolis: Five carries, 15 yards. Chicago: Three carries, 17 yards. At Houston: Eight for 31.

So often he’s called on as a situational sub, encouraged to get a just a few small chunks. He knows he’s a back who gets better as his workload increases, bright enough to solve defenses, rugged enough to wear down tacklers.

Gerhart chuckles thinking about the rough first quarter Peterson had in St. Louis last December. Eight rushes for 8 yards. Then came an 82-yard touchdown burst.

“Now he’s averaging 10 yards per carry and everything’s great,” Gerhart says. “For me, sometimes it’s two carries. You get the zero and the two. And that’s it.

“I hear it all the time from my buddies. ‘Stinks you only got two carries. But, hey, you’re backing up Adrian Peterson.’ Like it’s some sort of awesome consolation prize just because it’s Adrian.”

No wonder Gerhart’s dad, Todd, always has his cell phone ready, the one outlet Toby can always turn to for reassurance. More often than not, though, it’s a son persuading his dad that all will ultimately be OK.

“It’s funny,” Todd says. “He sells it to me. ‘My time will come. I’ll get my shot.’ I just listen. He’s telling it to me, I think, for his own psychotherapy.”

When the disenchantment rises, Gerhart reminds himself of the thousands of players who had similar NFL dreams but never stuck around this long. He counts his blessings that he’s healthy and able to work daily with the best player on the planet.

Naturally, he’ll peek around the league.

“Seems like everybody’s going to a two-back system but us,” he says. “But with the guy we have, it’s hard to go to a two-back share.”

Gerhart will never say so in advance. But when his rookie contract expires next March, he’s certain to go on a job hunt. Like Felton in 2012. Restless, eager, seeking opportunity.

“Eventually his day is going to come,” Frazier says. “And he’s going to shine. He’s a very good back. But part of our existence as an NFL player is understanding the role and accepting that role.”

At long last

Even when the right opportunity with the right fit came at the right time, Felton almost tripped through a trap door. Ten weeks after signing with the Vikings, he spent a Friday night drinking at the Towne Place Suites in Eden Prairie, got an urge for a chicken sandwich and made a 0.92-mile drive to McDonald’s.

An employee thought Felton was falling asleep behind the wheel and called police. Felton was arrested and cited for two misdemeanor counts of driving while impaired.

“That could have easily been the end of my career,” he says. “Definitely.”

The next morning Felton called his family in tears. Shaken, he also explained his side to the Vikings’ front office. He prayed for a second chance but knew the organization might see his arrest as an unwanted distraction from an unproven journeyman and cut him loose.

Frazier made his disappointment known in front of the entire team.

“But,” he says, “I saw something in Jerome that convinced me he made a mistake and would learn from it. … If we had let him go after that incident, I would have been surprised if he would have gotten picked up.”

Even with the second chance, Felton was exhausted and losing motivation. Peterson knows now the fullback has come so close to quitting on multiple occasions.

“Good thing he didn’t,” Peterson says with a smile.

After all, Peterson’s 2,097-yard season had Felton’s imprints all over it.

Felton’s Week 13 smash on Green Bay’s A.J. Hawk was his favorite block, part of a 210-yard Peterson eruption. Two weeks prior, he held a key fourth-quarter block on Detroit’s Erik Coleman long enough to spring Peterson for a 61-yard game-sealing touchdown. In St. Louis, he lit up Rams linebacker James Laurinaitis, clearing Peterson for that 82-yard score.

In totality, Peterson believes Felton’s blocks were “Worth 600-700 yards over the course of the season. Maybe more than that.”

So when a second journey into free agency approached, Felton had zero desire to go elsewhere. Sure, he and his agent played the game, fielding calls from other teams, using the Texans’ interest for leverage. But after so many seasons of misery and anxiety, Felton wasn’t searching for the highest bidder.

“There’s no way to value being comfortable and happy where you’re at,” he says. “Now I can relax. Now I can be myself.”

The feeling has been liberating. It’s one Gerhart hopes to experience.